Heat exchange unit

ABSTRACT

A heat exchange unit for heat pumps or air conditioners includes a box-like casing, a lower surface, an upper surface which is opposite the lower surface and which is spaced apart therefrom with respect to an axis of the casing, and a front surface which extends between the lower surface and the upper surface, the surfaces being defined on the casing. The heat exchange unit also includes a first opening and a second opening which are made on the casing, a channel which extends inside the casing between the first and second openings, a fan which is housed inside the casing, along the channel, and which is provided to move an air flow away from and towards the external environment with respect to the casing through the openings, and a heat exchanger which is placed in the channel, at least a portion of the fan and the heat exchanger being one below the other with respect to the axis.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No. 16/494,306, filed Sep. 15, 2019, which is a 371 National Phase of PCT/IB2018/051711, filed Mar. 14, 2018 and claims priority of Italian Patent Application No. 102017000028737, the entire contents of all of which are incorporated by reference herein as if fully set forth.

FIELD OF THE INVENTION

The present invention relates to a heat exchange unit for heat pumps or air conditioners.

The heat exchange unit according to the invention is used particularly, though not exclusively, in the technical sector of designing and constructing installations for climate control of buildings, for example, by using heat pumps, which provide for the use of one or more units which are arranged outside the building and which are provided to carry out an exchange of thermal energy between the air of the external environment with respect to the building and an operating fluid.

BACKGROUND

These external units are operationally connected to the so-called internal units which are arranged in the internal environments of the building in order to regulate the temperature and/or the humidity thereof.

In the technical sector set out, the external units typically comprise an external casing which is subdivided into two chambers including at least a first heat exchanger for a refrigerating fluid and a fan and a second heat exchanger, a fan and a compressor, respectively, in order to perform the function of an evaporator or a condenser for heating or cooling the internal environments with respect to the building.

In order to cope with the need to accommodate the above-mentioned elements, the external units typically have an excessive spatial requirement which determines a substantial visual impact of those units on the buildings. This condition is poorly compatible with the requirement to maintain the facades of buildings of artistic or historic interest in an unchanged state to the greatest possible extent.

The international patent application WO2007/099571 deals with this problem. However, the external unit for conditioners described in WO2007/099571 is subjected to a plurality of disadvantages, such as, for example, the need to keep the external unit raised from a base and/or to provide for suitable air pipes to allow the passage of the flow of air through the external unit for the correct operation thereof.

As a result, therefore, there is reduced freedom of positioning of the external unit of WO2007/099571. Furthermore, the solution of WO2007/099571 has at least local weakening in the lower wall of the external unit.

Additional examples of heat exchange devices are described in the patent documents JP 2011 149593 A, EP 3070410 A1 and WO 2004/083734. The devices described in the documents set out above are found to be poorly suitable for being fitted in walls as a result of the depth thereof which is relatively great and/or are found to be particularly detrimental to the aesthetic of the buildings as a result of the great front intake openings formed in these devices.

SUMMARY

The technical problem addressed by the present invention is therefore to provide a heat exchange unit for heat pumps or air conditioners which is functionally and structurally configured to overcome at least one of the disadvantages set out with reference to the prior art cited.

In the context of this problem, an object of the invention is to provide a heat exchange unit for heat pumps or air conditioners which can be arranged inside or outside a building in a simple and relatively economical manner.

Another object of the invention is to provide a heat exchange unit for heat pumps or air conditioners which is sufficiently robust.

Another object of the invention is to provide a heat exchange unit for heat pumps or air conditioners which has a small spatial requirement.

This problem is solved and at least one of these objects is achieved by means of a heat exchange unit for heat pumps or air conditioners which is made according to the claim appended to the present description.

Preferred features of the invention are defined in the dependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The features and additional advantages of the invention will be better appreciated from the following detailed description of a preferred though non-limiting embodiment thereof which is illustrated by way of non-limiting example with reference to the appended drawings, in which:

FIG. 1 is a schematic perspective front view of a heat exchange unit according to the invention,

FIG. 1A is a schematic perspective front view of a heat exchange unit according to the invention,

FIG. 2 is a schematic perspective rear view of the heat exchange unit of FIG. 2 ,

FIG. 3 is a schematic cross-section of the exchange unit of FIGS. 1 and 2 , sectioned by the plane of section a,

FIGS. 3A, 3B and 3C are schematic cross-sections of exchange units in accordance with embodiments of the invention, sectioned by the plane of section a,

FIGS. 4, 5 and 6 are schematic views of the exchange unit of FIG. 1 associated with an external wall of a building according to different techniques,

FIG. 7 is a cross-section of an exchange unit according to the invention arranged in a seat of an external wall of a building,

FIG. 8 is a schematic view of an exchange unit according to the invention arranged in an internal environment of a building and

FIG. 9 is a cross-section of an exchange unit according to the invention arranged according to FIG. 8 .

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In FIG. 1 there is generally designated 100 a heat exchange unit for heat pumps or air conditioners according to the invention.

According to an aspect of the invention, the heat exchange unit 100 is or can be operationally connected to one or more devices (generally referred to as internal units) which are arranged in the internal environments of a building in order to modify the temperature thereof and/or to sanitary (hot) water distribution devices and/or refrigeration devices.

The heat exchange unit 100 comprises a box-like casing 1, on which there are defined a lower surface 2, an opposite upper surface 3 and a front surface 4 which extends between the lower surface 2 and the upper surface 3. With reference to FIG. 1 , the upper surface 3 is spaced apart from the lower surface 2 with respect to an axis X of the casing 1, that is to say, in the direction of the axis X. Preferably, the axis X of the casing 1 is substantially orthogonal to the lower surface 2 of the casing 1. Preferably, the axis X is substantially vertical when the heat exchange unit 100 is in use.

According to an aspect of the invention, the casing 1 comprises a rear surface 5 which is opposite the front surface 4 and preferably a pair of lateral surfaces 25, 26 which are opposite each other so that the casing 1 preferably has a shape which can be compared to a parallelepiped, in particular a rectangular parallelepiped.

Preferably, the front surface 4 and more preferably also the rear surface 5 have a longitudinal extent in accordance with the axis X.

Preferably, the lateral surfaces 25, 26 have a longitudinal extent in accordance with the axis X. According to an aspect of the invention, the extent of the lateral surfaces 25, 26 in accordance with the axis Z illustrated in the Figures defines the depth of the heat exchange unit 100. The axis Z is normal to the axis X and in particular substantially horizontal when the heat exchange unit 100 is in use.

In the context of the present invention, the terms “lower surface” and “front surface” are intended to be understood to identify a surface of the casing 1 which is intended to be directed towards the ground and towards the external environment with respect to a building during use of the heat exchange unit 100, respectively.

The heat exchange unit 100 further comprises a first opening 6 and a second opening 7 which are made on the casing 1. Preferably, the openings 6 and 7 are made on the casing 1 in the form of a grid.

According to an embodiment of the invention, the heat exchange unit 100 comprises a channel 8 which extends inside the casing 1 between the first and second openings 6, 7, in particular from the first opening 6 as far as the second opening 7.

Preferably, the channel 8 extends mainly in accordance with the axis X of the casing 1.

With reference to FIG. 1 , a fan 9 is housed inside the casing 1, along the channel 8. The fan 9 is arranged to move an air flow (which is indicated in the Figures by the arrows designated 10) away from and towards the external environment with respect to the heat exchange unit 100, that is to say, the casing 1 through the openings 6, 7.

In particular, the fan 9 comprises an impeller 91 which can be rotated about an individual rotation axis Y inside the heat exchange unit casing 1. The heat exchange unit casing 1 is provided with an inlet opening 7, through which the air flow 10 is drawn by the rotation of the impeller 91, and an outlet 6 from which the drawn-in air flow 10 is discharged from the casing 1.

Preferably, the external environment with respect to the heat exchange unit 100 coincides with the external environment with respect to the building with which the heat exchange unit 100 is intended to be associated.

The heat exchange unit 100 further comprises a heat exchanger 11 placed in the channel 8 so that at least a portion of the fan 9 and the heat exchanger 11 are one below the other with respect to the axis X, preferably with the axis X orientated towards the upper surface 3. Preferably, at least a portion of the fan 9 is below the heat exchanger 11 with respect to the axis X.

In other words, at least a portion of the fan 9 is located in a lower or higher position (preferably lower) than the position of the heat exchanger 11 with respect to the axis X. Preferably, the entire fan 9 is spaced apart from the heat exchanger 11 along the axis X.

According to an aspect of the invention, the heat exchanger 11 is at least partially above the fan 9 with respect to the axis X (FIG. 3 ). Alternatively, the fan 9 can be at least partially above the heat exchanger 11 with respect to the axis X.

Preferably, the heat exchanger 11 is substantially aligned with the fan 9 along the axis X.

These features are found to be particularly advantageous in order to obtain a heat exchanger 100 having a reduced depth, which is thus particularly suitable for being recessed in a wall or partition wall of a building.

Preferably, the first opening 6 is made on the front surface 4 of the casing 1 and the second opening 7 is made on the upper surface 3 and/or on the front surface 4 in a position above the first opening 6 with respect to the axis X.

These features allow the lower surface 2 to be freed from the function of providing access for the circulation of the air flow 10 between the external environment and the internal environment of the casing 1 so that the heat exchange unit 100 can be readily placed on a base, as illustrated in FIG. 5 .

This results in a heat exchange unit 100 which can be arranged inside or outside a building in a simple and relatively economical manner.

Differently, the solution described in WO2007/099571 provides for the construction of at least one opening on the lower wall of the external unit for the passage of the air flow. The unit of WO2007/099571 therefore has to be kept raised from a base surface, for example, by means of suitable brackets, or, if placed on a base, there has to be provision for the construction of openings and air ducts in this base which allow the external unit to be placed in fluid communication with the external environment through the opening of the above-mentioned lower wall. This leads to an inevitable increase in the costs and the time taken to put the known unit into operation.

Furthermore, the fact of not providing for openings on the lower surface 2 prevents the structural weakening in this region of the casing 1, on which the weight of the unit bears when it is positioned on a base.

More generally, according to an aspect of the invention, the lower surface 2, the rear surface 5 and the lateral surfaces 25, 26 are closed, that is to say, are not provided with one or more openings for the passage of the air flow 10 away from and towards the external environment with respect to the casing 1.

This feature is found to be particularly advantageous in order to recess the heat exchange unit 100 in a wall or partition wall.

In addition, the fact that at least a portion of the fan 9 and the second opening 7 are spaced apart with respect to the axis X from the heat exchanger 11 and from the first opening 6, respectively, allows the thickness, that is to say, the depth, of the heat exchange unit 100 to be reduced, preferably in favour of the development thereof along the axis X. The unit 100 is thus found to be particularly suitable for being fixed in an overhanging manner to an external wall of a building or to be recessed in the external wall itself, as will be better described below.

According to an aspect of the invention, the first and the second openings 6, 7 are made on the front surface 4 and in the upper surface 3 of the casing 1, respectively. This is found to be particularly advantageous in terms of circulation of the air flow 10 away from and towards the external environment through the unit 100.

According to an aspect of the invention, the fan 9 is placed in the channel 8 between the first opening 6 and the heat exchanger 11. In this manner, the spacing between the fan 9 and the lower surface 2 is less than that between the lower face 2 and the heat exchanger 11.

Furthermore, this feature allows the formation in the front surface 4 of an opening 6 having a relatively limited extent, preferably substantially corresponding to the radial extent of the impeller 91 of the fan 9, thereby avoiding the construction of a considerable grid, with resultant advantages in terms of the aesthetic appearance which can be attributed to the heat exchange unit according to the invention.

Differently, the devices illustrated in JP 2011 149593 A, EP 3070410 A1 and WO 2004/083734 provide for the interposition of the heat exchange element between the respective fan/fans and the intake opening formed on the casing. This provision involves the production of a great front intake opening, which can be substantially compared with the extent of the heat exchange element, in order to produce a thermal energy exchange between the air and the operating fluid which circulates in the above-mentioned heat exchange element. These devices are therefore found to be aesthetically poorly suitable for being used outside buildings.

According to an aspect of the invention, the fan 9 is arranged to promote a circulation of the air flow 10 from the first opening 6 to the second opening 7.

This feature is found to be particularly advantageous in order to optimize the circulation of the air flow 10, this flow being drawn in by the fan 9 inside the channel 8 through the first opening 6 and discharged into the external environment via the second opening 7 after passing through the heat exchange unit 100.

With reference to FIG. 3 , the fan 9 is preferably placed in a position adjacent to the first opening 6 in such a manner that the impeller of the fan 9 faces the first opening 6. In this manner, one or more air filter(s) which is/are provided to remove any particulate present in the air flow 10 can be readily arranged in the space of the channel 8 between the fan 9 and the heat exchanger 11. The presence of the air filters mentioned above allows protection of the heat exchanger 11 from fine dust, preserving the correct operation thereof. Furthermore, this feature is found to be particularly advantageous for limiting the dimension in terms of depth of the heat exchange unit 100 so that it can readily be recessed in a wall of the building or arranged inside the building itself with minimal visual impact.

According to an aspect of the invention, the fan 9 is preferably of the centrifugal type (radial). Alternatively, the fan 9 may be of the axial type.

The provision of a centrifugal fan 9 advantageously allows an intake of air flow in a first direction and the air flow to be conveyed in a second direction which is normal to the first one.

Specifically, the air flow 10 is drawn inside the heat exchange unit casing 1 through the inlet opening 7 and is conveyed towards the heat exchange unit casing outlet opening 6 through which the air flow 10 is discharged from the heat exchange unit casing 1 mentioned above in a direction perpendicular to the rotation axis Y of the impeller 91.

According to an aspect of the invention, the rotation axis Y of the impeller 91 of the fan 9 is transverse, in particular orthogonal, to the axis X.

In this manner, the depth of the heat exchange unit according to the invention can be limited substantially to the spatial requirement of the fan 9 about the rotation axis Y, that is to say, the radial extent of the impeller 91 does not influence the dimensions of the depth of the heat exchange unit according to the invention.

Differently, the device described in JP 2011 149593 is provided with axial fans which are positioned in the region of the upper surface of the respective support structure, with a resultant great extent in terms of depth of the device as a result of the radial dimension of the impeller of the fans. This device is therefore found to be poorly suitable for being recessed in a wall.

Preferably, the rotation axis Y of the impeller 91 is substantially orthogonal to a vertical extent of the channel 8. Preferably, the fan 9 is arranged in such a manner that the impeller 91 faces the opening 6 which is made on the front surface 4.

In this manner, the centrifugal fan 9 is provided to draw in the air flow 10 in a first direction transverse to the front surface 4 and to direct this flow towards the upper surface 3 along the axis X, thereby improving the circulation of the air flow 10. The air flow 10 which is directed in the channel 8 therefore flows along the axis X in the direction of the heat exchanger 11 above the centrifugal fan 9, thus obtaining an efficient exchange of thermal energy between the air flow 10 and an operating fluid which circulates in the heat exchanger 11.

The fan 9 of the centrifugal type is characterized by a high static pressure which allows any possible losses of charge as a result of the friction between the air flow and the internal walls of the channel 8 to be made up.

According to an aspect of the invention, the heat exchanger 11 may have a V-shaped profile. In particular, the cross-section of the heat exchanger 11 obtained by sectioning it with a plane a parallel with the axis X, preferably parallel with the lateral surfaces 25, 26 of the casing 1, has a V-like shape.

This feature is found to be particularly advantageous for increasing the heat exchange surface of the heat exchanger 11 with respect, for example, to the heat exchanger in the form of a panel described in EP3070410 A1. On the other hand, the device described in WO 2004/083734 has a heat exchanger of U-like form which inevitably leads to an increase of the depth of the device, making it unsuitable for being recessed in walls of buildings.

Preferably, the heat exchanger 11 comprises a pair of panels 11 a, 11 b (also referred to as batteries) which are secured to each other at respective edges and arranged so as to confer on the heat exchanger 11 a V-like shape. The pair of panels 11 a, 11 b of the heat exchanger 11 are preferably inclined with respect to the axis X of the casing 1.

Preferably, the heat exchanger 11 has an upside-down V-like profile. In other words, the heat exchanger 11 has an inverted V-like formation with the vertex 11 c of the heat exchanger 11 which turns towards the upper surface 3. This provision confers on the heat exchanger 11 an inverted V-like formation with respect to the lower surface 2.

This feature is found to be particularly advantageous with the heat exchanger 11 positioned above the fan 9 of the centrifugal type. In fact, the air flow 10 being discharged from the fan 9 is thereby directed towards the vertex 11 c of the heat exchanger 11 in order to be discharged from the second opening 7 of the casing 1 after passing through the pair of panels 11 a, 11 b mentioned above.

With reference to FIG. 3 , the heat exchanger 11 is preferably arranged inside the channel 8 so as to be able to be passed through by the air flow 10 in order to bring about an exchange of thermal energy between the air flow 10 and an operating fluid which circulates in a coil of the heat exchanger 11.

The operating fluid may be a refrigerating fluid or water. The inverted V-like formation advantageously allows an increase in the efficiency of the heat exchange between the air flow 10 and the operating fluid of the heat exchanger 11.

Preferably, the heat exchange unit 100 comprises hydraulic and electrical connection means 16 which are provided to operationally connect the heat exchange unit 100 to one or more internal units and/or sanitary water distribution devices and/or refrigeration devices.

In particular, the hydraulic connection means operationally connect the coil of the heat exchanger 11 with pipes which are provided to convey the operating fluid from the coil towards the hydraulic circuits of the internal units and/or the above-mentioned devices, and vice versa.

According to an aspect of the invention, the heat exchange unit 100 comprises a pair of containers 12, 13 for collecting condensation water and which are placed in the region of respective distal ends 14, 15 of the heat exchanger 11 with respect to the vertex 11 c thereof. In this manner, the condensation water is prevented from flowing onto the fan 9.

With reference to FIGS. 2 and 3 , the rear surface 5 of the heat exchange unit 100 can be provided with first engagement means 17 arranged for being connected in a stable manner to second engagement means 18, these means being able to be fixed to an external wall of a building in order to support the casing 1. Preferably, the first and second engagement means 17, 18 are constructed in an eyelet-like manner and hook-like manner, respectively. Alternatively, the rear surface 5 is provided with one or more hooks which are provided with respective brackets for fixing the hooks to a wall.

In an embodiment of the invention, the heat exchange unit 100 may further comprise a compressor which is housed in the casing 1 and which is operationally connected to the heat exchanger 11.

With reference to FIGS. 6 and 7 , the heat exchange unit 100 can be at least partially arranged inside a seat 19 which is formed in an external wall 20 of a building. This seat 19 can be formed in the construction phase of the building.

The casing 1 can be stabilized in the seat 19 by means of the use of the first and second engagement means 17, 18, the second engagement means 18 being fixed to a rear wall 21 of the seat 19.

If the second opening 7 is made on the upper surface 3 of the casing 1, it is preferable to construct the seat 19 in such a manner that there is defined between the upper surface 3 of the casing 1 and the upper surface 23 of the seat 19 a space 22 which is sufficiently great to ensure the circulation of the flow 10 and the correct operation of the heat exchange unit 100 when it is housed in the seat 19.

Preferably, the space 22 is closed with respect to the external environment by means of a panel which is provided with a grid for the passage of the air flow 10.

A conveyor 26 a may be provided inside the space 22 between the second opening 7 of the casing 1 and the panel which closes the space 22 at the front.

The seat 19 can be closed with respect to the external environment by means of a front panel 24 in such a manner that the front surface 4 of the casing 1 is substantially near the internal surface of the front panel 24. The front panel 24 is preferably provided with a pair of grids which are placed in the region of the first opening 6 and the second opening 7, respectively, or the space 22 if provided, in order to allow the circulation of the air flow 10.

With reference to FIGS. 8 and 9 , the heat exchange unit 100 can be at least partially arranged in an internal environment of a building. In this case, the front surface 4 of the casing 1 faces the internal surface of an external wall 20 of the building.

The openings 6, 7 of the casing 1 are connected at the exterior of the building by means of respective openings 27, 28 which are made on the external wall 20 and preferably protected by an anti-intrusion grid. A conveyor 26 b may be provided between the second opening 7 of the casing 1 and the internal surface of the external wall 20 of the building.

As a result of one feature or the combination of a plurality of features of the invention described above, the depth of the heat exchange unit 100 may be between 30 and 40 cm. The height of the heat exchange unit 100, that is to say, the extent thereof along the axis X, may be between 90 and 160 cm while the width may be between 100 and 140 cm.

The heating power of the heat exchange unit 100 may be between 5 and 25 KW.

The invention thereby solves the problem set, at the same time achieving a plurality of advantages. In particular, the invention solves the problem of the difficulty of arrangement of a heat exchange unit for heat pumps or air conditioners, at the same time maintaining a small spatial requirement of the heat exchange unit itself. 

What is claimed is:
 1. A heat exchange unit for heat pumps or air conditioners, comprising: a box-like casing, a lower surface, an upper surface which is opposite the lower surface and which is spaced apart therefrom with respect to an axis (X) of the casing, and a front surface which extends between the lower surface and the upper surface, the surfaces being defined on the casing, a first opening and a second opening which are made on the casing, a channel which extends inside the casing between the first and second openings, a fan housed inside the casing, along the channel, and which is arranged to move an air flow away from and towards the external environment with respect to the casing through the openings, the fan being a radial fan, wherein the fan has an open impeller arranged to diffuse the air flow in the channel radially in relation to the rotation axis (Y) of the impeller, a heat exchanger placed in the channel, in which the heat exchanger has a V-like profile and at least a portion of the fan and the heat exchanger are one below the other with respect to the axis (X), wherein the first opening is made on the front surface of the casing and the second opening is made on the upper surface and/or on the front surface in a position above the first opening with respect to the axis (X), wherein the heat exchange unit is an external unit, and wherein the front surface of the heat exchange unit is directed towards the external environment with respect to a building during use of the heat exchange unit.
 2. A heat exchange unit according to claim 1, wherein the first and second openings are made on the front surface and on the upper surface of the casing, respectively.
 3. A heat exchange unit according to claim 1, wherein the fan is placed in the channel between the first opening and the heat exchanger.
 4. A heat exchange unit according to claim 1, wherein the fan is arranged to promote a circulation of the air flow from the first opening to the second opening.
 5. A heat exchange unit according to claim 1, wherein rotation axis (Y) of the impeller of the fan is transverse, in particular orthogonal, to the axis (X).
 6. A heat exchange unit according to claim 1, wherein the fan is placed in a position adjacent to the first opening in such a manner that an impeller of the fan faces the first opening.
 7. A heat exchange unit according to claim 1, wherein the vertex of the heat exchanger turns towards the upper surface.
 8. A heat exchange unit according to claim 7, wherein the heat exchange unit comprises a pair of containers for collecting condensation water, which are placed in the region of respective distal ends of the heat exchanger with respect to the vertex thereof.
 9. A heat exchange unit according to claim 1, wherein the box-shaped casing further comprises a rear surface opposite the front surface and a pair of lateral surface which are opposite each other, the lower surface, rear surface and lateral surfaces not being provided with one or more openings for the passage of the air flow away from and towards the external environment with respect to the casing.
 10. A heat exchange unit according to claim 1, wherein the heat exchanger is at least partially above the fan with respect to the axis (X) of the casing.
 11. A heat exchange unit according to claim 1, wherein the heat exchanger is substantially aligned with the fan along the axis (X) of the casing.
 12. A heat exchange unit according to claim 1, wherein the heat exchange unit comprises hydraulic and electrical connection means which are provided to operationally connect the heat exchange unit to one or more internal units of a conditioning installation and/or sanitary water distribution devices and/or refrigeration devices.
 13. The heat exchange unit according to claim 1, wherein the second opening is made on the front surface in a position above the first opening with respect to the axis (X).
 14. The heat exchange unit according to claim 13, wherein the heat exchange unit comprises an elbow conveyor placed at the second opening for the circulation of the air flow, the second opening being made on the casing in the form of a grid.
 15. The heat exchange unit according to claim 1, wherein a seat is formed in an external wall of a building and the heat exchange unit is at least partially arranged inside the seat.
 16. The heat exchange unit according to claim 15, wherein the seat is closed with respect to the external environment by means of a front panel in such a manner that the front surface of the casing is substantially near an internal surface of the front panel.
 17. The heat exchange unit according to claim 2, wherein a seat is formed in an external wall of a building and the heat exchange unit is at least partially arranged inside the seat so that a space is defined between the upper surface of the casing and an upper surface of the seat, wherein a conveyor is provided in the space between the second opening of the casing and a panel which closes the space at the front, the panel being provided with a grid for the passage of the air flow.
 18. The heat exchange unit according to claim 1, wherein the rear surface of the heat exchange unit is provided with first engagement means arranged for being connected in a stable manner to second engagement means, these means being able to be fixed to an external wall of a building in order to support the casing.
 19. The heat exchange unit according to claim 18, wherein the first and second engagement means are constructed in an eyelet-like manner and hooklike manner, respectively.
 20. The heat exchange unit according to claim 1, wherein the box-shaped casing further comprises a rear surface opposite the front surface and wherein the rear surface is provided with one or more hooks which are provided with respective brackets for fixing the hooks to a wall. 